A significant portion of the generator weight in modern electrical power generating systems is contributed by the generator housing. Where the generator is part of a moving vehicle or an aircraft, energy efficiency and performance requirements dictate that the weight of the generator including the generator housing be as low as possible. In the past, generator housings for aircraft generators have been formed of metal. Metal forming techniques such as die casting and post casting machining processes have facilitated the construction of the generator housings in the desired form. While relatively lightweight, nonmetallic materials are, per se, known, it can be difficult to fabricate complex structures, particularly those containing complex internal passages, with such materials in a technically acceptable and costeffective manner.
One known type of generator utilized in aircraft is a brushless generator. The brushless generator typically has three distinct generating systems, including a main generator, an exciter and a permanent magnet generator. The permanent magnet generator includes permanent magnets for establishing a magnetic field which is employed to induce a voltage in a set of windings. The current produced as a result is in turn employed to produce a magnetic field in the exciter; and this magnetic field in turn is employed to induce an even higher level of current, typically three-phase alternating, which is then employed to produce a magnetic field for the main generator.
In order to avoid the use of brushes, it is necessary that the magnetic field of the main generator be in the rotor so that the output of the system can be taken from the stator of the main generator. To generate a suitable magnetic field in the rotor, it is necessary to utilize direct current, as opposed to alternating current. Since the output of the exciter is an alternating current, this current must be rectified to direct current. A rectifier assembly is used for this purpose. In order to avoid resorting to brushes, it is necessary that the rectifier assembly interconnecting the exciter and the main generator field winding be carried by the rotor of the generator. U.S. Pat. Nos. 4,570,094; 4,603,344 and 4,628,219 disclose examples of known rotating rectifier assemblies.
The diode semiconductor devices used in the rectifier assemblies dissipate power in the form of heat during their use. Without proper attention to cooling, the diode semiconductor devices will fail. In the known rotating rectifier assemblies of the aforementioned U.S. Patents, the diode semiconductor devices and other assembly components are compressed in a direction along the axis of rotation of the rectifier assembly for maintaining good electrical contact and for maintaining contact of the diode wafers with adjacent heat sinks. The cooling of the diode semiconductor devices is accomplished by circulation of a coolant in contact with the heat sinks. Cooling of the other components of the generator such as the main stator, exciter, and permanent magnet generator stators 10 is also important for maintaining performance of the generator. For this purpose, internal fluid coolant such as oil is necessary. The oil also serves as a gear and bearing lubricant.
It is known from U.S. Pat. Nos. 3,495,604; 3,506,024 and 3,534,755 to construct fluidic amplifiers or the like by assembling a plurality of laminae each having different fluid passageways therethrough. U.S. Pat. No. 4,807,342, relates to a heat exchanger structure formed of a plurality of laminae. U.S. Pat. 4,828,184 concerns a nozzle formed of two laminae.